It has been known for many years that the use of so called honeycomb elements disposed in an air nozzle through which air is discharged can perform an airflow straightening function as well as in effect increasing the throw of the air through the straightening function. It has also been known to applicant's assignee from experimentation that a honeycomb flow straightener applied in the discharge air outlet or nozzle of a transport refrigeration unit could provide improved evaporator air throw. However such straighteners were not applied commercially because they were not considered necessary in view of the relatively shorter trailers then in use for the most part. However the desirability of the use of honeycomb flow straighteners may be considered to be increasing in view of somewhat longer trailers presenting the problem of getting sufficient air throw to the rear end of the trailer.
In most of the transport refrigeration units used on trailers the unit is capable of providing either cooling or heating, or if cooling only, some means is provided to defrost the refrigerant evaporator coil of the unit. When the coil is being defrosted, ordinary practice is to close an airflow damper, to prevent the flow of air through the evaporator while the defrosting operation is going on. The defrost damper is ordinarily located in the air discharge nozzle space where a honeycomb flow straightener would best be located if to be within the confines of the unit. While a defrost damper can be located other than in the air discharge nozzle, such a relocation would create problems with respect to other internal equipment already located in ways which would interfere with a relocation of the defrost damper.
It is the aim of my invention to provide an arrangement in which a honeycomb airflow straightener assembly is located in the air discharge nozzle passage and, it is unnecessary to relocate the defrost damper.